②Thecountrysidehaschangedalotinthepastfewyears.在过去的几年，农村发生了巨大的变化。
一、一般现在时
1、概念：表示经常发生的情况；有规律出现的情况；总是发生的；事实真理。
2.时间状语: Always, usually, often, sometimes, every week (day, year, month…), once a week (day, year, month…), on Sundays (on Mondays…), etc.
3.基本结构：主语 动词原形（如主语为第三人称单数，动词上要改为第三人称单数形式）
4.否定形式：主语 am / is / are not 其他；此时态的谓语动词若为行为动词，则在其前加 don't，如主语为第三人称单数，则用 doesn't，同时还原行为动词。
5.一般疑问句：把 be 动词放于句首；用助动词 do 提问，如主语为第三人称单数，则用 does，同时，还原行为动词。
eg：
①It seldom snows here. 这里很少下雪。
②He is always ready to help others. 他总是乐于帮助别人。
③Action speaks louder than words. 事实胜雄辩。
二、一般过去时
1.概念：过去某个时间里发生的动作或状态；过去习惯性、经常性的动作、行为。
2.时间状语：ago, yesterday, the day before yesterday, last week, last (year,night,month…), in 1989, just now, at the age of 5, one day, long long ago, once upon a time,etc.
3.基本结构：主语 动词的过去式或 be 的过去式 名词
4.否定形式：主语 was / were not 其他；在行为动词前加didn't，同时还原行为动词。
5.一般疑问句：was 或 were 放于句首；用助动词 do 的过去式 did 提问，同时还原行为动词。
eg：
①She often came to help us in those days.那些天她经常来帮助我们。
②I didn't know you were so busy.我不知道你这么忙。
三、一般将来时
1.概念：表示将要发生的动作或存在的状态及打算、计划或准备做某事。
2.时间状语：Tomorrow, next day (week,month, year…), soon, in a few minutes, by…, the day after tomorrow,etc.
3.基本结构：主语 am/is / are going to do 其它；主语 will / shall do 其它
4.否定形式：主语 am /is/ are not going to do；主语 will / shall not do 其它
5.一般疑问句：be 放于句首；will / shall 提到句首。（首字母大写）
eg：
①They are going to have a competition with us in studies.他们将在学习中与我们竞争。
②It is going to rain.天要下雨了。
四、一般过去将来时
1.概念：立足于过去某一时刻，从过去看将来，常用于宾语从句中。
2.时间状语：The next day (morning, year…), the following month (week…), etc.
3.基本结构：主语 was / were going to do 其它；主语 would / should do 其它
4.否定形式：主语 was / were not going to do 其它；主语 would/should not do.
5.一般疑问句：was 或 were 放于句首；would / should 提到句首
eg：
①He said he would go to Beijing the next day. 他说他第二天要去北京。
②I asked who was going there. 我问，谁要去那里。
五、现在进行时
1.概念：表示现阶段或说话时正在进行的动作及行为。
2.时间状语：Now, at this time, days, look, listen, etc.
3.基本结构：主语 be doing 其它
4.否定形式：主语 be not doing 其它
5.一般疑问句：把be动词放于句首。
eg：
①Are you feeling good today?你今天感觉如何？
②He is doing well in his lessons.在课上他表现得很好。
六、过去进行时
1.概念：表示过去某段时间或某一时刻正在发生或进行的行为或动作。
2.时间状语：at this time yesterday, at that time 或以 when 引导的谓语动词是一般过去时的时间状语等。
3.基本结构: 主语 was / were doing 其它
4.否定形式：主语 was/were not doing 其它
5.一般疑问句：把 was 或 were 放于句首。（第一个字母大写）
eg：
①At that time she was working in a company. 那段时间她在一家公司工作。
②When he came in, I was reading a newspaper. 他进来时，我正在读报纸。
七、现在完成时
1.概念：过去发生或已经完成的动作对现在造成的影响或结果,或从过去已经开始，持续到现在的动作或状态。
2.时间状语：yet, already, just, never, ever, so far, by now, since 时间点，for 时间段，recently, lately, in the past few years,etc.
3.基本结构：主语 have / has 过去分词 其它
4.否定形式：主语 have / has not 过去分词 其它
5.一般疑问句：have 或 has 放句首。
eg：
①I've written an article. 我已经写了一篇论文。
②The countryside has changed a lot in the past few years. 在过去的几年，农村发生了巨大的变化。
八、过去完成时
1.概念：过去发生或者已经完成的动作对现在造成的影响或结果，或从过去已经开始，持续到现在的动作或状态。
2.时间状语：before, by the end of last year (term, month), etc.
3.基本结构：had done.
4.否定形式：had not done.
5.一般疑问句：had 放于句首。
6.用法：
（1）在told, said, knew, heard, thought等动词后的宾语从句中。
eg：
She said (that) she had never been to Paris. 她告诉我她从来没有去过巴黎。
（2）在过去不同时间发生的两个动作中，发生在先，用过去完成时;发生在后，用一般过去时。
eg：
①When the police arrived, the thieves had run away. 警察到达时，小偷们早就跑了。
（3）表示意向的动词，如hope, wish, expect, think, intend, mean,suppose等，用过去完成时表示"原本…，未能…"。
eg：
①We had hoped that you would come, but you didn't. 那时我们希望你能来，但是你没有来。
②I had hardly opened the door when he hit me. 我刚打开门，他就打了我。
（注意：had hardly… when... 刚......就......）
③He had no sooner bought the car than he sold it. 他刚买了这辆车，转眼又卖了。
（注意：had no sooner…than 刚…… 就……）
